On 07.02.2014, at 02:33, Scott Wood <scottw...@freescale.com> wrote:
> On Thu, 2014-02-06 at 12:11 +0100, Alexander Graf wrote:
>> On 04.02.2014, at 03:52, Scott Wood <scottw...@freescale.com> wrote:
>>
>>> On Fri, 2014-01-31 at 12:16 +0100, Alexander Graf wrote:
>>>> The only thing we know in our PV machine through device tree is the clock
>>>> speed of the CPUs. Take that as CPU speed, system speed and ddr speed so
>>>> that
>>>> we have some meaningful values there at all.
>>>>
>>>> The CPU speed is important because our timing loops get determined based
>>>> on it.
>>>>
>>>> Signed-off-by: Alexander Graf <ag...@suse.de>
>>>> ---
>>>> arch/powerpc/cpu/mpc85xx/Makefile | 2 ++
>>>> board/freescale/qemu-ppce500/qemu-ppce500.c | 43
>>>> +++++++++++++++++++++++++++
>>>> 2 files changed, 45 insertions(+)
>>>>
>>>> diff --git a/arch/powerpc/cpu/mpc85xx/Makefile
>>>> b/arch/powerpc/cpu/mpc85xx/Makefile
>>>> index ef7637a..4094785 100644
>>>> --- a/arch/powerpc/cpu/mpc85xx/Makefile
>>>> +++ b/arch/powerpc/cpu/mpc85xx/Makefile
>>>> @@ -102,7 +102,9 @@ obj-y += cpu.o
>>>> obj-y += cpu_init.o
>>>> obj-y += cpu_init_early.o
>>>> obj-y += interrupts.o
>>>> +ifneq ($(CONFIG_QEMU_E500),y)
>>>> obj-y += speed.o
>>>> +endif
>>>> obj-y += tlb.o
>>>> obj-y += traps.o
>>>>
>>>> diff --git a/board/freescale/qemu-ppce500/qemu-ppce500.c
>>>> b/board/freescale/qemu-ppce500/qemu-ppce500.c
>>>> index 5d4dd64..9e9d688 100644
>>>> --- a/board/freescale/qemu-ppce500/qemu-ppce500.c
>>>> +++ b/board/freescale/qemu-ppce500/qemu-ppce500.c
>>>> @@ -407,3 +407,46 @@ void init_laws(void)
>>>> {
>>>> /* We don't emulate LAWs yet */
>>>> }
>>>> +
>>>> +static uint32_t get_cpu_freq(void)
>>>> +{
>>>> + const void *fdt = get_fdt();
>>>> + int cpus_node = fdt_path_offset(fdt, "/cpus");
>>>> + int cpu_node = fdt_first_subnode(fdt, cpus_node);
>>>> + return myfdt_one_cell(fdt, cpu_node, "clock-frequency", 0);
>>>> +}
>>>> +
>>>> +void get_sys_info(sys_info_t *sys_info)
>>>> +{
>>>> + int freq = get_cpu_freq();
>>>> +
>>>> + memset(sys_info, 0, sizeof(sys_info_t));
>>>> + sys_info->freq_systembus = freq;
>>>> + sys_info->freq_ddrbus = freq;
>>>> + sys_info->freq_processor[0] = freq;
>>>> +}
>>>> +
>>>> +int get_clocks (void)
>>>> +{
>>>> + sys_info_t sys_info;
>>>> +
>>>> + get_sys_info(&sys_info);
>>>> +
>>>> + gd->cpu_clk = sys_info.freq_processor[0];
>>>> + gd->bus_clk = sys_info.freq_systembus;
>>>> + gd->mem_clk = sys_info.freq_ddrbus;
>>>> + gd->arch.lbc_clk = sys_info.freq_ddrbus;
>>>> +
>>>> + return 0;
>>>> +}
>>>
>>> This probably decreases the accuracy of the timebase frequency, since
>>> you'll be basing it on the CPU frequency rather than the bus frequency.
>>>
>>> If you're doing this, why not override get_tbclk() as well?
>>
>> That one only uses variables I already control, no?
>>
>> unsigned long get_tbclk (void)
>> {
>> unsigned long tbclk_div = CONFIG_SYS_FSL_TBCLK_DIV;
>>
>> return (gd->bus_clk + (tbclk_div >> 1)) / tbclk_div;
>> }
>
> What did you set CONFIG_SYS_FSL_TBCLK_DIV to?
Nothing which is why it's defaulting to 8.
Alex
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